Posts tagged with XMP

How does Lightroom handle custom XMP?

There’s been no change to LR’s handling of custom XMP since version 1 – I’d characterise it as “preserving” custom XMP data.

So LR does read the data from imported files and stores it in a database field. It never displays the information and it isn’t editable even through the SDK. But at least Lightroom doesn’t do any damage. When you save metadata back to the original files (sidecars or directly into the file) it does not overwrite any custom XMP it encounters, and it does write the custom XMP to any exported files.

It is possible to use a plug-in that calls an external library (exiftools) to read and write custom XMP. I have one working for myself, but I judged the area’s complexity and potential for damage to be so great that I’ve chosen not to develop it for wider use. I’d make far too many enemies!

Does History matter?

Does the order of steps in the History panel make any difference to the end result?

The answer is an emphatic No. Lightroom edits do not build on one another – the current slider values in the right hand panel are all that matters.

If you don’t quite believe this, save the edits back to xmp and remove the image from the catalogue. Reimport it and there’ll be no History – but the image will look identical to before.

The History panel is more like a log of what you’ve done – an audit trail – and I’ve long thought Adobe could have used a different term, like “log”, to clearly distinguish it from Photoshop’s History feature, where the exact order of work does often matter.

Of course, it is not merely a log. One nice touch is when you’re in Before/After view (Y) you can drag history steps into the Before view.